Because of the health threat to children, California in 2003 banned idling of school buses. Under the state law, California school bus drivers must turn off their engines when they arrive and restart them no earlier than 30 seconds before departing.
At least 17 other states also have state or local rules that limit idling, some for all vehicles and others for just buses.
In most cities, kids’ exposure is greatest while they are actually inside the bus. According to one study in Los Angeles, people are exposed to 40 times more exhaust while riding in a bus than they are while waiting at the bus stop.
But in New York City, pollution at bus stops is unusually high because of urban street canyons--tall buildings and narrow streets that trap pollution at the street level. Particulates at ground level can be up to 175 percent higher than on the rooftops, depending on which direction the wind is blowing.
In the new study, air quality was monitored over 16 days at the end of the school day. Monitoring devices were positioned near the Reece School, which is also near two other East Harlem schools. Minute-by-minute readings were taken of particulate matter and black carbon and the results were compared to background pollution, according to the study, which was published in the journal Science of the Total Environment.
The researchers found that fine particulates were higher than black carbon, but changes in concentration were not related to traffic, suggesting that the street canyon was trapping the particles. Black carbon concentrations, however, were significantly related to idling and passing diesel vehicles. Because background data on black carbon have never been recorded, researchers are unable to say whether it is significantly higher during the dismissal period.
The findings have prompted several environmental and community groups to start developing policies and educational programs to manage traffic, improve air quality, and reduce absenteeism related to asthma attacks.
When the Asthma Free School Zone was founded, director Rebecca Kalin took on the idling problem by targeting the worst offenders.
“The most egregious example was yellow school buses, and nobody seemed to be paying attention at all,” said Kalin.
After a phone call in 2004 to then Attorney General Eliot Spitzer, a representative from Mayor Michael R. Bloomberg’s office met with Kalin the next day, and within eight months, the city sued the largest school bus companies, forcing the school bus operators to train drivers to limit idling.
In April, the maximum idling time in a school zone was reduced from three minutes (the maximum time elsewhere in the city) to one minute. The law, however, is difficult to monitor and rarely enforced.
A spokesperson for the New York City Department of Education said there is little that schools can do to make sure bus drivers comply because buses are privately operated and enforcement is the police department’s job.
“I’m really concerned about the city situation, but it’s improving all the time,” Kalin said. There’s a loop-hole in the law that exempts private schools and doesn’t require them to post no idling signs, she said.
The New York Department of Environmental Conservation granted traffic enforcement officers the authority to ticket school buses that violate idling laws in an effort to encourage bus companies to retrofit their buses. The fines begin at $220, and reach $2,000 for repeat offenders.
Isabelle Silverman, an attorney with the Environmental Defense Fund, said it makes sense to allow these officers to ticket idlers since “they are out there walking the streets, breathing in the pollution.”
“We want them to fix the problem, not to just have to pay,” said Anhthu Hoang, General Counsel for West Harlem Environmental Action, Inc., a community environmental justice group. “We want them to lower their emissions.”